We are interested in signal transduction pathways between the external stimuli generated at the plasma membrane and cellular and viral genes that can regulate gene expression and cell division. The raf oncogene a serine threonine kinase, appears to function to provide a link from membrane signals to nuclear events. Therefore, we have investigated the possible role raf kinase plays in transmitting information to the nucleus to modulate expression of cellular or viral genes. Our data suggests that the raf kinase may directly or indirectly activate the long terminal repeats (LTRs) of HIV, HTLV as well as the immediate-early (IE) promoter of the cytomegalovirus (CMV). The activation of the raf oncogene may not only play a role in cellular transformation but it may be an important determinant of HIV, HTLV and CMV latency as well.